Made less numbers on the dyno, but I didnt change anything?

Hey on Friday I tried to finally finish my car. We strapped it down and it put 329 down first run. Last time I was there I made 338. Next try i made 367 but Paul said it was because of my clutch slipping and it really wasnt that high. After somemore tuning it was back to 320-330 but never above 330. What happened? I didnt change anything since last time I was there. I thought I would make some more power with a chip and some tuning but I lost some? Dyno time was cut short becausse of leaking coolant but it wasnt my HG from what I know. So far it looks to be my waterpump.
 
Here is a graph of the the time before where we had NO tuning(just dropped f/p a little). Could those bumps in the power curve be from my clutch slipping cause they wouldnt go away.

dyno_graph_002.jpg
 
Sorry reading comp owns me. missed that. there is still some margin for error but your right. I would have hoped to pick up a few HP from the chip and air temp. Who programmed the chip. can you go back to your original tune and re dyno? Your original tune might have been a little less conservitive then your new tune. better safe then sorry. Where was your timing and A/F last verses now?
 
well there is also one other factor that could be at hand.. I have found this out personally. The belt on the blower could and probably slips. I have went from 9 psi one run to 12 the next to 8 the next...

I always thought that blower belt slipage was just an excuse guys came up with till i saw it do it on my datalog. You could see how it would climb and then come down cause it would start to slip...

The only cure for this is a cog system that i know about.